Skin, especially those portions of the skin not often covered by clothing, is regularly exposed to the environment. So, when the environment to which one is exposed contains air pollution, your skin is also exposed to the air pollution. While we can sense dirt or grime deposited on the skin from air pollution, we cannot tell by looking whether that dirt or grime contains airborne elements, like metals, from the pollution. As such, there is a need to detect and measure airborne metal pollutants on skin.